/* ***************************************************************************
 *
 * ftimage.h
 *
 * FreeType glyph image formats and default raster interface
 * (specification).
 *
 * Copyright (C) 1996-2021 by
 * David Turner, Robert Wilhelm, and Werner Lemberg.
 *
 * This file is part of the FreeType project, and may only be used,
 * modified, and distributed under the terms of the FreeType project
 * license, LICENSE.TXT.  By continuing to use, modify, or distribute
 * this file you indicate that you have read the license and
 * understand and accept it fully.
 *
 */

/* *************************************************************************
 *
 * Note: A 'raster' is simply a scan-line converter, used to render
 * FT_Outlines into FT_Bitmaps.
 *
 */


#ifndef FTIMAGE_H_
#define FTIMAGE_H_


FT_BEGIN_HEADER


/* *************************************************************************
 *
 * @section:
 * basic_types
 *
 */


/* *************************************************************************
 *
 * @type:
 * FT_Pos
 *
 * @description:
 * The type FT_Pos is used to store vectorial coordinates.  Depending on
 * the context, these can represent distances in integer font units, or
 * 16.16, or 26.6 fixed-point pixel coordinates.
 */
typedef signed long FT_Pos;


/* *************************************************************************
 *
 * @struct:
 * FT_Vector
 *
 * @description:
 * A simple structure used to store a 2D vector; coordinates are of the
 * FT_Pos type.
 *
 * @fields:
 * x ::
 * The horizontal coordinate.
 * y ::
 * The vertical coordinate.
 */
typedef struct FT_Vector_ {
    FT_Pos x;
    FT_Pos y;
} FT_Vector;


/* *************************************************************************
 *
 * @struct:
 * FT_BBox
 *
 * @description:
 * A structure used to hold an outline's bounding box, i.e., the
 * coordinates of its extrema in the horizontal and vertical directions.
 *
 * @fields:
 * xMin ::
 * The horizontal minimum (left-most).
 *
 * yMin ::
 * The vertical minimum (bottom-most).
 *
 * xMax ::
 * The horizontal maximum (right-most).
 *
 * yMax ::
 * The vertical maximum (top-most).
 *
 * @note:
 * The bounding box is specified with the coordinates of the lower left
 * and the upper right corner.  In PostScript, those values are often
 * called (llx,lly) and (urx,ury), respectively.
 *
 * If `yMin` is negative, this value gives the glyph's descender.
 * Otherwise, the glyph doesn't descend below the baseline.  Similarly,
 * if `ymax` is positive, this value gives the glyph's ascender.
 *
 * `xMin` gives the horizontal distance from the glyph's origin to the
 * left edge of the glyph's bounding box.  If `xMin` is negative, the
 * glyph extends to the left of the origin.
 */
typedef struct FT_BBox_ {
    FT_Pos xMin, yMin;
    FT_Pos xMax, yMax;
} FT_BBox;


/* *************************************************************************
 *
 * @enum:
 * FT_Pixel_Mode
 *
 * @description:
 * An enumeration type used to describe the format of pixels in a given
 * bitmap.  Note that additional formats may be added in the future.
 *
 * @values:
 * FT_PIXEL_MODE_NONE ::
 * Value~0 is reserved.
 *
 * FT_PIXEL_MODE_MONO ::
 * A monochrome bitmap, using 1~bit per pixel.  Note that pixels are
 * stored in most-significant order (MSB), which means that the
 * left-most pixel in a byte has value 128.
 *
 * FT_PIXEL_MODE_GRAY ::
 * An 8-bit bitmap, generally used to represent anti-aliased glyph
 * images.  Each pixel is stored in one byte.  Note that the number of
 * 'gray' levels is stored in the `num_grays` field of the @FT_Bitmap
 * structure (it generally is 256).
 *
 * FT_PIXEL_MODE_GRAY2 ::
 * A 2-bit per pixel bitmap, used to represent embedded anti-aliased
 * bitmaps in font files according to the OpenType specification.  We
 * haven't found a single font using this format, however.
 *
 * FT_PIXEL_MODE_GRAY4 ::
 * A 4-bit per pixel bitmap, representing embedded anti-aliased bitmaps
 * in font files according to the OpenType specification.  We haven't
 * found a single font using this format, however.
 *
 * FT_PIXEL_MODE_LCD ::
 * An 8-bit bitmap, representing RGB or BGR decimated glyph images used
 * for display on LCD displays; the bitmap is three times wider than
 * the original glyph image.  See also @FT_RENDER_MODE_LCD.
 *
 * FT_PIXEL_MODE_LCD_V ::
 * An 8-bit bitmap, representing RGB or BGR decimated glyph images used
 * for display on rotated LCD displays; the bitmap is three times
 * taller than the original glyph image.  See also
 * @FT_RENDER_MODE_LCD_V.
 *
 * FT_PIXEL_MODE_BGRA ::
 * [Since 2.5] An image with four 8-bit channels per pixel,
 * representing a color image (such as emoticons) with alpha channel.
 * For each pixel, the format is BGRA, which means, the blue channel
 * comes first in memory.  The color channels are pre-multiplied and in
 * the sRGB colorspace.  For example, full red at half-translucent
 * opacity will be represented as '00,00,80,80', not '00,00,FF,80'.
 * See also @FT_LOAD_COLOR.
 */
typedef enum FT_Pixel_Mode_ {
    FT_PIXEL_MODE_NONE = 0,
    FT_PIXEL_MODE_MONO,
    FT_PIXEL_MODE_GRAY,
    FT_PIXEL_MODE_GRAY2,
    FT_PIXEL_MODE_GRAY4,
    FT_PIXEL_MODE_LCD,
    FT_PIXEL_MODE_LCD_V,
    FT_PIXEL_MODE_BGRA,

    FT_PIXEL_MODE_MAX /* do not remove */

} FT_Pixel_Mode;


/* these constants are deprecated; use the corresponding `FT_Pixel_Mode` */
/* values instead.                                                       */
#define ft_pixel_mode_none FT_PIXEL_MODE_NONE
#define ft_pixel_mode_mono FT_PIXEL_MODE_MONO
#define ft_pixel_mode_grays FT_PIXEL_MODE_GRAY
#define ft_pixel_mode_pal2 FT_PIXEL_MODE_GRAY2
#define ft_pixel_mode_pal4 FT_PIXEL_MODE_GRAY4

/* */

/* For debugging, the @FT_Pixel_Mode enumeration must stay in sync */
/* with the `pixel_modes` array in file `ftobjs.c`.                */


/* *************************************************************************
 *
 * @struct:
 * FT_Bitmap
 *
 * @description:
 * A structure used to describe a bitmap or pixmap to the raster.  Note
 * that we now manage pixmaps of various depths through the `pixel_mode`
 * field.
 *
 * @fields:
 * rows ::
 * The number of bitmap rows.
 *
 * width ::
 * The number of pixels in bitmap row.
 *
 * pitch ::
 * The pitch's absolute value is the number of bytes taken by one
 * bitmap row, including padding.  However, the pitch is positive when
 * the bitmap has a 'down' flow, and negative when it has an 'up' flow.
 * In all cases, the pitch is an offset to add to a bitmap pointer in
 * order to go down one row.
 *
 * Note that 'padding' means the alignment of a bitmap to a byte
 * border, and FreeType functions normally align to the smallest
 * possible integer value.
 *
 * For the B/W rasterizer, `pitch` is always an even number.
 *
 * To change the pitch of a bitmap (say, to make it a multiple of 4),
 * use @FT_Bitmap_Convert.  Alternatively, you might use callback
 * functions to directly render to the application's surface; see the
 * file `example2.cpp` in the tutorial for a demonstration.
 *
 * buffer ::
 * A typeless pointer to the bitmap buffer.  This value should be
 * aligned on 32-bit boundaries in most cases.
 *
 * num_grays ::
 * This field is only used with @FT_PIXEL_MODE_GRAY; it gives the
 * number of gray levels used in the bitmap.
 *
 * pixel_mode ::
 * The pixel mode, i.e., how pixel bits are stored.  See @FT_Pixel_Mode
 * for possible values.
 *
 * palette_mode ::
 * This field is intended for paletted pixel modes; it indicates how
 * the palette is stored.  Not used currently.
 *
 * palette ::
 * A typeless pointer to the bitmap palette; this field is intended for
 * paletted pixel modes.  Not used currently.
 */
typedef struct FT_Bitmap_ {
    unsigned int rows;
    unsigned int width;
    int pitch;
    unsigned char *buffer;
    unsigned short num_grays;
    unsigned char pixel_mode;
    unsigned char palette_mode;
    void *palette;
} FT_Bitmap;


/* *************************************************************************
 *
 * @section:
 * outline_processing
 *
 */


/* *************************************************************************
 *
 * @struct:
 * FT_Outline
 *
 * @description:
 * This structure is used to describe an outline to the scan-line
 * converter.
 *
 * @fields:
 * n_contours ::
 * The number of contours in the outline.
 *
 * n_points ::
 * The number of points in the outline.
 *
 * points ::
 * A pointer to an array of `n_points` @FT_Vector elements, giving the
 * outline's point coordinates.
 *
 * tags ::
 * A pointer to an array of `n_points` chars, giving each outline
 * point's type.
 *
 * If bit~0 is unset, the point is 'off' the curve, i.e., a Bezier
 * control point, while it is 'on' if set.
 *
 * Bit~1 is meaningful for 'off' points only.  If set, it indicates a
 * third-order Bezier arc control point; and a second-order control
 * point if unset.
 *
 * If bit~2 is set, bits 5-7 contain the drop-out mode (as defined in
 * the OpenType specification; the value is the same as the argument to
 * the 'SCANMODE' instruction).
 *
 * Bits 3 and~4 are reserved for internal purposes.
 *
 * contours ::
 * An array of `n_contours` shorts, giving the end point of each
 * contour within the outline.  For example, the first contour is
 * defined by the points '0' to `contours[0]`, the second one is
 * defined by the points `contours[0]+1` to `contours[1]`, etc.
 *
 * flags ::
 * A set of bit flags used to characterize the outline and give hints
 * to the scan-converter and hinter on how to convert/grid-fit it.  See
 * @FT_OUTLINE_XXX.
 *
 * @note:
 * The B/W rasterizer only checks bit~2 in the `tags` array for the first
 * point of each contour.  The drop-out mode as given with
 * @FT_OUTLINE_IGNORE_DROPOUTS, @FT_OUTLINE_SMART_DROPOUTS, and
 * @FT_OUTLINE_INCLUDE_STUBS in `flags` is then overridden.
 */
typedef struct FT_Outline_ {
    short n_contours; /* number of contours in glyph        */
    short n_points;   /* number of points in the glyph      */

    FT_Vector *points; /* the outline's points               */
    char *tags;        /* the points flags                   */
    short *contours;   /* the contour end points             */

    int flags; /* outline masks                      */
} FT_Outline;

/* */

/* Following limits must be consistent with */
/* FT_Outline.{n_contours,n_points}         */
#define FT_OUTLINE_CONTOURS_MAX SHRT_MAX
#define FT_OUTLINE_POINTS_MAX SHRT_MAX


/* *************************************************************************
 *
 * @enum:
 * FT_OUTLINE_XXX
 *
 * @description:
 * A list of bit-field constants used for the flags in an outline's
 * `flags` field.
 *
 * @values:
 * FT_OUTLINE_NONE ::
 * Value~0 is reserved.
 *
 * FT_OUTLINE_OWNER ::
 * If set, this flag indicates that the outline's field arrays (i.e.,
 * `points`, `flags`, and `contours`) are 'owned' by the outline
 * object, and should thus be freed when it is destroyed.
 *
 * FT_OUTLINE_EVEN_ODD_FILL ::
 * By default, outlines are filled using the non-zero winding rule.  If
 * set to 1, the outline will be filled using the even-odd fill rule
 * (only works with the smooth rasterizer).
 *
 * FT_OUTLINE_REVERSE_FILL ::
 * By default, outside contours of an outline are oriented in
 * clock-wise direction, as defined in the TrueType specification.
 * This flag is set if the outline uses the opposite direction
 * (typically for Type~1 fonts).  This flag is ignored by the scan
 * converter.
 *
 * FT_OUTLINE_IGNORE_DROPOUTS ::
 * By default, the scan converter will try to detect drop-outs in an
 * outline and correct the glyph bitmap to ensure consistent shape
 * continuity.  If set, this flag hints the scan-line converter to
 * ignore such cases.  See below for more information.
 *
 * FT_OUTLINE_SMART_DROPOUTS ::
 * Select smart dropout control.  If unset, use simple dropout control.
 * Ignored if @FT_OUTLINE_IGNORE_DROPOUTS is set.  See below for more
 * information.
 *
 * FT_OUTLINE_INCLUDE_STUBS ::
 * If set, turn pixels on for 'stubs', otherwise exclude them.  Ignored
 * if @FT_OUTLINE_IGNORE_DROPOUTS is set.  See below for more
 * information.
 *
 * FT_OUTLINE_OVERLAP ::
 * This flag indicates that this outline contains overlapping contrours
 * and the anti-aliased renderer should perform oversampling to
 * mitigate possible artifacts.  This flag should _not_ be set for
 * well designed glyphs without overlaps because it quadruples the
 * rendering time.
 *
 * FT_OUTLINE_HIGH_PRECISION ::
 * This flag indicates that the scan-line converter should try to
 * convert this outline to bitmaps with the highest possible quality.
 * It is typically set for small character sizes.  Note that this is
 * only a hint that might be completely ignored by a given
 * scan-converter.
 *
 * FT_OUTLINE_SINGLE_PASS ::
 * This flag is set to force a given scan-converter to only use a
 * single pass over the outline to render a bitmap glyph image.
 * Normally, it is set for very large character sizes.  It is only a
 * hint that might be completely ignored by a given scan-converter.
 *
 * @note:
 * The flags @FT_OUTLINE_IGNORE_DROPOUTS, @FT_OUTLINE_SMART_DROPOUTS, and
 * @FT_OUTLINE_INCLUDE_STUBS are ignored by the smooth rasterizer.
 *
 * There exists a second mechanism to pass the drop-out mode to the B/W
 * rasterizer; see the `tags` field in @FT_Outline.
 *
 * Please refer to the description of the 'SCANTYPE' instruction in the
 * OpenType specification (in file `ttinst1.doc`) how simple drop-outs,
 * smart drop-outs, and stubs are defined.
 */
#define FT_OUTLINE_NONE 0x0
#define FT_OUTLINE_OWNER 0x1
#define FT_OUTLINE_EVEN_ODD_FILL 0x2
#define FT_OUTLINE_REVERSE_FILL 0x4
#define FT_OUTLINE_IGNORE_DROPOUTS 0x8
#define FT_OUTLINE_SMART_DROPOUTS 0x10
#define FT_OUTLINE_INCLUDE_STUBS 0x20
#define FT_OUTLINE_OVERLAP 0x40

#define FT_OUTLINE_HIGH_PRECISION 0x100
#define FT_OUTLINE_SINGLE_PASS 0x200


/* these constants are deprecated; use the corresponding */
/* `FT_OUTLINE_XXX` values instead                       */
#define ft_outline_none FT_OUTLINE_NONE
#define ft_outline_owner FT_OUTLINE_OWNER
#define ft_outline_even_odd_fill FT_OUTLINE_EVEN_ODD_FILL
#define ft_outline_reverse_fill FT_OUTLINE_REVERSE_FILL
#define ft_outline_ignore_dropouts FT_OUTLINE_IGNORE_DROPOUTS
#define ft_outline_high_precision FT_OUTLINE_HIGH_PRECISION
#define ft_outline_single_pass FT_OUTLINE_SINGLE_PASS

/* */

#define FT_CURVE_TAG(flag) (flag & 0x03)

/* see the `tags` field in `FT_Outline` for a description of the values */
#define FT_CURVE_TAG_ON 0x01
#define FT_CURVE_TAG_CONIC 0x00
#define FT_CURVE_TAG_CUBIC 0x02

#define FT_CURVE_TAG_HAS_SCANMODE 0x04

#define FT_CURVE_TAG_TOUCH_X 0x08 /* reserved for TrueType hinter */
#define FT_CURVE_TAG_TOUCH_Y 0x10 /* reserved for TrueType hinter */

#define FT_CURVE_TAG_TOUCH_BOTH (FT_CURVE_TAG_TOUCH_X | FT_CURVE_TAG_TOUCH_Y)
/* values 0x20, 0x40, and 0x80 are reserved */


/* these constants are deprecated; use the corresponding */
/* `FT_CURVE_TAG_XXX` values instead                     */
#define FT_Curve_Tag_On FT_CURVE_TAG_ON
#define FT_Curve_Tag_Conic FT_CURVE_TAG_CONIC
#define FT_Curve_Tag_Cubic FT_CURVE_TAG_CUBIC
#define FT_Curve_Tag_Touch_X FT_CURVE_TAG_TOUCH_X
#define FT_Curve_Tag_Touch_Y FT_CURVE_TAG_TOUCH_Y


/* *************************************************************************
 *
 * @functype:
 * FT_Outline_MoveToFunc
 *
 * @description:
 * A function pointer type used to describe the signature of a 'move to'
 * function during outline walking/decomposition.
 *
 * A 'move to' is emitted to start a new contour in an outline.
 *
 * @input:
 * to ::
 * A pointer to the target point of the 'move to'.
 *
 * user ::
 * A typeless pointer, which is passed from the caller of the
 * decomposition function.
 *
 * @return:
 * Error code.  0~means success.
 */
typedef int (*FT_Outline_MoveToFunc)(const FT_Vector *to, void *user);

#define FT_Outline_MoveTo_Func FT_Outline_MoveToFunc


/* *************************************************************************
 *
 * @functype:
 * FT_Outline_LineToFunc
 *
 * @description:
 * A function pointer type used to describe the signature of a 'line to'
 * function during outline walking/decomposition.
 *
 * A 'line to' is emitted to indicate a segment in the outline.
 *
 * @input:
 * to ::
 * A pointer to the target point of the 'line to'.
 *
 * user ::
 * A typeless pointer, which is passed from the caller of the
 * decomposition function.
 *
 * @return:
 * Error code.  0~means success.
 */
typedef int (*FT_Outline_LineToFunc)(const FT_Vector *to, void *user);

#define FT_Outline_LineTo_Func FT_Outline_LineToFunc


/* *************************************************************************
 *
 * @functype:
 * FT_Outline_ConicToFunc
 *
 * @description:
 * A function pointer type used to describe the signature of a 'conic to'
 * function during outline walking or decomposition.
 *
 * A 'conic to' is emitted to indicate a second-order Bezier arc in the
 * outline.
 *
 * @input:
 * control ::
 * An intermediate control point between the last position and the new
 * target in `to`.
 *
 * to ::
 * A pointer to the target end point of the conic arc.
 *
 * user ::
 * A typeless pointer, which is passed from the caller of the
 * decomposition function.
 *
 * @return:
 * Error code.  0~means success.
 */
typedef int (*FT_Outline_ConicToFunc)(const FT_Vector *control, const FT_Vector *to, void *user);

#define FT_Outline_ConicTo_Func FT_Outline_ConicToFunc


/* *************************************************************************
 *
 * @functype:
 * FT_Outline_CubicToFunc
 *
 * @description:
 * A function pointer type used to describe the signature of a 'cubic to'
 * function during outline walking or decomposition.
 *
 * A 'cubic to' is emitted to indicate a third-order Bezier arc.
 *
 * @input:
 * control1 ::
 * A pointer to the first Bezier control point.
 *
 * control2 ::
 * A pointer to the second Bezier control point.
 *
 * to ::
 * A pointer to the target end point.
 *
 * user ::
 * A typeless pointer, which is passed from the caller of the
 * decomposition function.
 *
 * @return:
 * Error code.  0~means success.
 */
typedef int (*FT_Outline_CubicToFunc)(const FT_Vector *control1, const FT_Vector *control2, const FT_Vector *to,
    void *user);

#define FT_Outline_CubicTo_Func FT_Outline_CubicToFunc


/* *************************************************************************
 *
 * @struct:
 * FT_Outline_Funcs
 *
 * @description:
 * A structure to hold various function pointers used during outline
 * decomposition in order to emit segments, conic, and cubic Beziers.
 *
 * @fields:
 * move_to ::
 * The 'move to' emitter.
 *
 * line_to ::
 * The segment emitter.
 *
 * conic_to ::
 * The second-order Bezier arc emitter.
 *
 * cubic_to ::
 * The third-order Bezier arc emitter.
 *
 * shift ::
 * The shift that is applied to coordinates before they are sent to the
 * emitter.
 *
 * delta ::
 * The delta that is applied to coordinates before they are sent to the
 * emitter, but after the shift.
 *
 * @note:
 * The point coordinates sent to the emitters are the transformed version
 * of the original coordinates (this is important for high accuracy
 * during scan-conversion).  The transformation is simple:
 *
 * ```
 * x' = (x << shift) - delta
 * y' = (y << shift) - delta
 * ```
 *
 * Set the values of `shift` and `delta` to~0 to get the original point
 * coordinates.
 */
typedef struct FT_Outline_Funcs_ {
    FT_Outline_MoveToFunc move_to;
    FT_Outline_LineToFunc line_to;
    FT_Outline_ConicToFunc conic_to;
    FT_Outline_CubicToFunc cubic_to;

    int shift;
    FT_Pos delta;
} FT_Outline_Funcs;


/* *************************************************************************
 *
 * @section:
 * basic_types
 *
 */


/* *************************************************************************
 *
 * @macro:
 * FT_IMAGE_TAG
 *
 * @description:
 * This macro converts four-letter tags to an unsigned long type.
 *
 * @note:
 * Since many 16-bit compilers don't like 32-bit enumerations, you should
 * redefine this macro in case of problems to something like this:
 *
 * ```
 * #define FT_IMAGE_TAG( value, _x1, _x2, _x3, _x4 )  value
 * ```
 *
 * to get a simple enumeration without assigning special numbers.
 */
#ifndef FT_IMAGE_TAG

#define FT_IMAGE_TAG(value, _x1, _x2, _x3, _x4)                                                                  \
    value = ((FT_STATIC_BYTE_CAST(unsigned long, _x1) << 24) | (FT_STATIC_BYTE_CAST(unsigned long, _x2) << 16) | \
        (FT_STATIC_BYTE_CAST(unsigned long, _x3) << 8) | FT_STATIC_BYTE_CAST(unsigned long, _x4))

#endif /* FT_IMAGE_TAG */


/* *************************************************************************
 *
 * @enum:
 * FT_Glyph_Format
 *
 * @description:
 * An enumeration type used to describe the format of a given glyph
 * image.  Note that this version of FreeType only supports two image
 * formats, even though future font drivers will be able to register
 * their own format.
 *
 * @values:
 * FT_GLYPH_FORMAT_NONE ::
 * The value~0 is reserved.
 *
 * FT_GLYPH_FORMAT_COMPOSITE ::
 * The glyph image is a composite of several other images.  This format
 * is _only_ used with @FT_LOAD_NO_RECURSE, and is used to report
 * compound glyphs (like accented characters).
 *
 * FT_GLYPH_FORMAT_BITMAP ::
 * The glyph image is a bitmap, and can be described as an @FT_Bitmap.
 * You generally need to access the `bitmap` field of the
 * @FT_GlyphSlotRec structure to read it.
 *
 * FT_GLYPH_FORMAT_OUTLINE ::
 * The glyph image is a vectorial outline made of line segments and
 * Bezier arcs; it can be described as an @FT_Outline; you generally
 * want to access the `outline` field of the @FT_GlyphSlotRec structure
 * to read it.
 *
 * FT_GLYPH_FORMAT_PLOTTER ::
 * The glyph image is a vectorial path with no inside and outside
 * contours.  Some Type~1 fonts, like those in the Hershey family,
 * contain glyphs in this format.  These are described as @FT_Outline,
 * but FreeType isn't currently capable of rendering them correctly.
 */
typedef enum FT_Glyph_Format_ {
    FT_IMAGE_TAG(FT_GLYPH_FORMAT_NONE, 0, 0, 0, 0),

    FT_IMAGE_TAG(FT_GLYPH_FORMAT_COMPOSITE, 'c', 'o', 'm', 'p'),
    FT_IMAGE_TAG(FT_GLYPH_FORMAT_BITMAP, 'b', 'i', 't', 's'),
    FT_IMAGE_TAG(FT_GLYPH_FORMAT_OUTLINE, 'o', 'u', 't', 'l'),
    FT_IMAGE_TAG(FT_GLYPH_FORMAT_PLOTTER, 'p', 'l', 'o', 't')

} FT_Glyph_Format;


/* these constants are deprecated; use the corresponding */
/* `FT_Glyph_Format` values instead.                     */
#define ft_glyph_format_none FT_GLYPH_FORMAT_NONE
#define ft_glyph_format_composite FT_GLYPH_FORMAT_COMPOSITE
#define ft_glyph_format_bitmap FT_GLYPH_FORMAT_BITMAP
#define ft_glyph_format_outline FT_GLYPH_FORMAT_OUTLINE
#define ft_glyph_format_plotter FT_GLYPH_FORMAT_PLOTTER


/* *********************************************************************** */
/* *********************************************************************** */
/* *********************************************************************** */
/* ****                                                               **** */
/* ****            R A S T E R   D E F I N I T I O N S                **** */
/* ****                                                               **** */
/* *********************************************************************** */
/* *********************************************************************** */
/* *********************************************************************** */


/* *************************************************************************
 *
 * @section:
 * raster
 *
 * @title:
 * Scanline Converter
 *
 * @abstract:
 * How vectorial outlines are converted into bitmaps and pixmaps.
 *
 * @description:
 * A raster or a rasterizer is a scan converter in charge of producing a
 * pixel coverage bitmap that can be used as an alpha channel when
 * compositing a glyph with a background.  FreeType comes with two
 * rasterizers: bilevel `raster1` and anti-aliased `smooth` are two
 * separate modules.  They are usually called from the high-level
 * @FT_Load_Glyph or @FT_Render_Glyph functions and produce the entire
 * coverage bitmap at once, while staying largely invisible to users.
 *
 * Instead of working with complete coverage bitmaps, it is also possible
 * to intercept consecutive pixel runs on the same scanline with the same
 * coverage, called _spans_, and process them individually.  Only the
 * `smooth` rasterizer permits this when calling @FT_Outline_Render with
 * @FT_Raster_Params as described below.
 *
 * Working with either complete bitmaps or spans it is important to think
 * of them as colorless coverage objects suitable as alpha channels to
 * blend arbitrary colors with a background.  For best results, it is
 * recommended to use gamma correction, too.
 *
 * This section also describes the public API needed to set up alternative
 * @FT_Renderer modules.
 *
 * @order:
 * FT_Span
 * FT_SpanFunc
 * FT_Raster_Params
 * FT_RASTER_FLAG_XXX
 *
 * FT_Raster
 * FT_Raster_NewFunc
 * FT_Raster_DoneFunc
 * FT_Raster_ResetFunc
 * FT_Raster_SetModeFunc
 * FT_Raster_RenderFunc
 * FT_Raster_Funcs
 *
 */


/* *************************************************************************
 *
 * @struct:
 * FT_Span
 *
 * @description:
 * A structure to model a single span of consecutive pixels when
 * rendering an anti-aliased bitmap.
 *
 * @fields:
 * x ::
 * The span's horizontal start position.
 *
 * len ::
 * The span's length in pixels.
 *
 * coverage ::
 * The span color/coverage, ranging from 0 (background) to 255
 * (foreground).
 *
 * @note:
 * This structure is used by the span drawing callback type named
 * @FT_SpanFunc that takes the y~coordinate of the span as a parameter.
 *
 * The anti-aliased rasterizer produces coverage values from 0 to 255,
 * this is, from completely transparent to completely opaque.
 */
typedef struct FT_Span_ {
    short x;
    unsigned short len;
    unsigned char coverage;
} FT_Span;


/* *************************************************************************
 *
 * @functype:
 * FT_SpanFunc
 *
 * @description:
 * A function used as a call-back by the anti-aliased renderer in order
 * to let client applications draw themselves the pixel spans on each
 * scan line.
 *
 * @input:
 * y ::
 * The scanline's upward y~coordinate.
 *
 * count ::
 * The number of spans to draw on this scanline.
 *
 * spans ::
 * A table of `count` spans to draw on the scanline.
 *
 * user ::
 * User-supplied data that is passed to the callback.
 *
 * @note:
 * This callback allows client applications to directly render the spans
 * of the anti-aliased bitmap to any kind of surfaces.
 *
 * This can be used to write anti-aliased outlines directly to a given
 * background bitmap using alpha compositing.  It can also be used for
 * oversampling and averaging.
 */
typedef void (*FT_SpanFunc)(int y, int count, const FT_Span *spans, void *user);

#define FT_Raster_Span_Func FT_SpanFunc


/* *************************************************************************
 *
 * @functype:
 * FT_Raster_BitTest_Func
 *
 * @description:
 * Deprecated, unimplemented.
 */
typedef int (*FT_Raster_BitTest_Func)(int y, int x, void *user);


/* *************************************************************************
 *
 * @functype:
 * FT_Raster_BitSet_Func
 *
 * @description:
 * Deprecated, unimplemented.
 */
typedef void (*FT_Raster_BitSet_Func)(int y, int x, void *user);


/* *************************************************************************
 *
 * @enum:
 * FT_RASTER_FLAG_XXX
 *
 * @description:
 * A list of bit flag constants as used in the `flags` field of a
 * @FT_Raster_Params structure.
 *
 * @values:
 * FT_RASTER_FLAG_DEFAULT ::
 * This value is 0.
 *
 * FT_RASTER_FLAG_AA ::
 * This flag is set to indicate that an anti-aliased glyph image should
 * be generated.  Otherwise, it will be monochrome (1-bit).
 *
 * FT_RASTER_FLAG_DIRECT ::
 * This flag is set to indicate direct rendering.  In this mode, client
 * applications must provide their own span callback.  This lets them
 * directly draw or compose over an existing bitmap.  If this bit is
 * _not_ set, the target pixmap's buffer _must_ be zeroed before
 * rendering and the output will be clipped to its size.
 *
 * Direct rendering is only possible with anti-aliased glyphs.
 *
 * FT_RASTER_FLAG_CLIP ::
 * This flag is only used in direct rendering mode.  If set, the output
 * will be clipped to a box specified in the `clip_box` field of the
 * @FT_Raster_Params structure.  Otherwise, the `clip_box` is
 * effectively set to the bounding box and all spans are generated.
 *
 * FT_RASTER_FLAG_SDF ::
 * This flag is set to indicate that a signed distance field glyph
 * image should be generated.  This is only used while rendering with
 * the @FT_RENDER_MODE_SDF render mode.
 */
#define FT_RASTER_FLAG_DEFAULT 0x0
#define FT_RASTER_FLAG_AA 0x1
#define FT_RASTER_FLAG_DIRECT 0x2
#define FT_RASTER_FLAG_CLIP 0x4
#define FT_RASTER_FLAG_SDF 0x8

/* these constants are deprecated; use the corresponding */
/* `FT_RASTER_FLAG_XXX` values instead                   */
#define ft_raster_flag_default FT_RASTER_FLAG_DEFAULT
#define ft_raster_flag_aa FT_RASTER_FLAG_AA
#define ft_raster_flag_direct FT_RASTER_FLAG_DIRECT
#define ft_raster_flag_clip FT_RASTER_FLAG_CLIP


/* *************************************************************************
 *
 * @struct:
 * FT_Raster_Params
 *
 * @description:
 * A structure to hold the parameters used by a raster's render function,
 * passed as an argument to @FT_Outline_Render.
 *
 * @fields:
 * target ::
 * The target bitmap.
 *
 * source ::
 * A pointer to the source glyph image (e.g., an @FT_Outline).
 *
 * flags ::
 * The rendering flags.
 *
 * gray_spans ::
 * The gray span drawing callback.
 *
 * black_spans ::
 * Unused.
 *
 * bit_test ::
 * Unused.
 *
 * bit_set ::
 * Unused.
 *
 * user ::
 * User-supplied data that is passed to each drawing callback.
 *
 * clip_box ::
 * An optional span clipping box expressed in _integer_ pixels
 * (not in 26.6 fixed-point units).
 *
 * @note:
 * The @FT_RASTER_FLAG_AA bit flag must be set in the `flags` to
 * generate an anti-aliased glyph bitmap, otherwise a monochrome bitmap
 * is generated.  The `target` should have appropriate pixel mode and its
 * dimensions define the clipping region.
 *
 * If both @FT_RASTER_FLAG_AA and @FT_RASTER_FLAG_DIRECT bit flags
 * are set in `flags`, the raster calls an @FT_SpanFunc callback
 * `gray_spans` with `user` data as an argument ignoring `target`.  This
 * allows direct composition over a pre-existing user surface to perform
 * the span drawing and composition.  To optionally clip the spans, set
 * the @FT_RASTER_FLAG_CLIP flag and `clip_box`.  The monochrome raster
 * does not support the direct mode.
 *
 * The gray-level rasterizer always uses 256 gray levels.  If you want
 * fewer gray levels, you have to use @FT_RASTER_FLAG_DIRECT and reduce
 * the levels in the callback function.
 */
typedef struct FT_Raster_Params_ {
    const FT_Bitmap *target;
    const void *source;
    int flags;
    FT_SpanFunc gray_spans;
    FT_SpanFunc black_spans;         /* unused */
    FT_Raster_BitTest_Func bit_test; /* unused */
    FT_Raster_BitSet_Func bit_set;   /* unused */
    void *user;
    FT_BBox clip_box;
} FT_Raster_Params;


/* *************************************************************************
 *
 * @type:
 * FT_Raster
 *
 * @description:
 * An opaque handle (pointer) to a raster object.  Each object can be
 * used independently to convert an outline into a bitmap or pixmap.
 *
 * @note:
 * In FreeType 2, all rasters are now encapsulated within specific
 * @FT_Renderer modules and only used in their context.
 *
 */
typedef struct FT_RasterRec_ *FT_Raster;


/* *************************************************************************
 *
 * @functype:
 * FT_Raster_NewFunc
 *
 * @description:
 * A function used to create a new raster object.
 *
 * @input:
 * memory ::
 * A handle to the memory allocator.
 *
 * @output:
 * raster ::
 * A handle to the new raster object.
 *
 * @return:
 * Error code.  0~means success.
 *
 * @note:
 * The `memory` parameter is a typeless pointer in order to avoid
 * un-wanted dependencies on the rest of the FreeType code.  In practice,
 * it is an @FT_Memory object, i.e., a handle to the standard FreeType
 * memory allocator.  However, this field can be completely ignored by a
 * given raster implementation.
 */
typedef int (*FT_Raster_NewFunc)(void *memory, FT_Raster *raster);

#define FT_Raster_New_Func FT_Raster_NewFunc


/* *************************************************************************
 *
 * @functype:
 * FT_Raster_DoneFunc
 *
 * @description:
 * A function used to destroy a given raster object.
 *
 * @input:
 * raster ::
 * A handle to the raster object.
 */
typedef void (*FT_Raster_DoneFunc)(FT_Raster raster);

#define FT_Raster_Done_Func FT_Raster_DoneFunc


/* *************************************************************************
 *
 * @functype:
 * FT_Raster_ResetFunc
 *
 * @description:
 * FreeType used to provide an area of memory called the 'render pool'
 * available to all registered rasterizers.  This was not thread safe,
 * however, and now FreeType never allocates this pool.
 *
 * This function is called after a new raster object is created.
 *
 * @input:
 * raster ::
 * A handle to the new raster object.
 *
 * pool_base ::
 * Previously, the address in memory of the render pool.  Set this to
 * `NULL`.
 *
 * pool_size ::
 * Previously, the size in bytes of the render pool.  Set this to 0.
 *
 * @note:
 * Rasterizers should rely on dynamic or stack allocation if they want to
 * (a handle to the memory allocator is passed to the rasterizer
 * constructor).
 */
typedef void (*FT_Raster_ResetFunc)(FT_Raster raster, unsigned char *pool_base, unsigned long pool_size);

#define FT_Raster_Reset_Func FT_Raster_ResetFunc


/* *************************************************************************
 *
 * @functype:
 * FT_Raster_SetModeFunc
 *
 * @description:
 * This function is a generic facility to change modes or attributes in a
 * given raster.  This can be used for debugging purposes, or simply to
 * allow implementation-specific 'features' in a given raster module.
 *
 * @input:
 * raster ::
 * A handle to the new raster object.
 *
 * mode ::
 * A 4-byte tag used to name the mode or property.
 *
 * args ::
 * A pointer to the new mode/property to use.
 */
typedef int (*FT_Raster_SetModeFunc)(FT_Raster raster, unsigned long mode, void *args);

#define FT_Raster_Set_Mode_Func FT_Raster_SetModeFunc


/* *************************************************************************
 *
 * @functype:
 * FT_Raster_RenderFunc
 *
 * @description:
 * Invoke a given raster to scan-convert a given glyph image into a
 * target bitmap.
 *
 * @input:
 * raster ::
 * A handle to the raster object.
 *
 * params ::
 * A pointer to an @FT_Raster_Params structure used to store the
 * rendering parameters.
 *
 * @return:
 * Error code.  0~means success.
 *
 * @note:
 * The exact format of the source image depends on the raster's glyph
 * format defined in its @FT_Raster_Funcs structure.  It can be an
 * @FT_Outline or anything else in order to support a large array of
 * glyph formats.
 *
 * Note also that the render function can fail and return a
 * `FT_Err_Unimplemented_Feature` error code if the raster used does not
 * support direct composition.
 */
typedef int (*FT_Raster_RenderFunc)(FT_Raster raster, const FT_Raster_Params *params);

#define FT_Raster_Render_Func FT_Raster_RenderFunc


/* *************************************************************************
 *
 * @struct:
 * FT_Raster_Funcs
 *
 * @description:
 * A structure used to describe a given raster class to the library.
 *
 * @fields:
 * glyph_format ::
 * The supported glyph format for this raster.
 *
 * raster_new ::
 * The raster constructor.
 *
 * raster_reset ::
 * Used to reset the render pool within the raster.
 *
 * raster_render ::
 * A function to render a glyph into a given bitmap.
 *
 * raster_done ::
 * The raster destructor.
 */
typedef struct FT_Raster_Funcs_ {
    FT_Glyph_Format glyph_format;

    FT_Raster_NewFunc raster_new;
    FT_Raster_ResetFunc raster_reset;
    FT_Raster_SetModeFunc raster_set_mode;
    FT_Raster_RenderFunc raster_render;
    FT_Raster_DoneFunc raster_done;
} FT_Raster_Funcs;

/* */


FT_END_HEADER

#endif /* FTIMAGE_H_ */


/* END */


/* Local Variables: */
/* coding: utf-8    */
/* End:             */
